During road construction, storm drains (also known as catch basins) and sewer inlets are disposed at various points along the road to evacuate excess water and/or debris that may accumulate. Such accumulation can occur for example during rainfall.
The storm drains (or catch basins) are connected to a system which is a network of pipes, pumps, and force mains for the collection of wastewater, or sewage, from the community. Typically, storm drains use a separate and distinct network from sanitary sewer systems for human waste. Sometimes a combined system provides only one network for all types of sewage and excess water or debris.
In order to evacuate the excess water and debris toward the system, the storm drain includes an inlet disposed on the road surface. Two main types of inlets exist: the side inlet and the grated inlet. The typically ends in an outlet for the water which is a single large exit at the point of discharge. The separation of storm sewers from sanitary sewers helps to prevent sewage treatment plants becoming overwhelmed by infiltration/inflow during a rainstorm, which can result in untreated sewage being discharged into the environment.
The grated inlets prevent pedestrians, vehicles and large objects from falling into the storm drain. The design of the grate bars facilitates a flow of water towards the inside of the drain. Storm drains provided in streets and parking areas must be strong enough to support the weight of the vehicles. Some of the heavier sediment and small objects or debris may enter the grated inlet and settle in the catchbasin below the inlet. A frame is provided for the catchbasin or catch pit and the grate covers the open top of the frame of the catchbasin. The frame supports the grate/cover.
It is common to have the frames disposed floatingly on the catch basin/manhole inlets. In a floating arrangement, the concrete constituting the road is poured around the sides of the frame and provides the connection between the road and the frame. No additional connection is used to secure the frame to the road. As such, movements between the road and the frame, which could happen during frosting and defrosting periods, is absorbed by the relative flexibility of the connection between them. To install the frame while pouring the concrete to make the road, the frame is first inserted in a guiding holder. The guiding holder is fixedly connected to the catch basin inlet. Wood shims are used to position the frame in place into the guiding holder. An inconvenience with that method is that the wooden shims may displace during the concrete pouring operation, which in turn can induce imprecise alignment between the frame and the catch basin. Over time, water infiltration can occur and premature wear of the frame and its connection to the road can happen.
To reduce the imprecision of the wood shim technique, some have fixedly attached the frame into the concrete road. However, any further adjustment is prevented and replacement of portions of the road would be needed should the frame need to be changed.